Stapler



FIG. 1 is a left side elevational view of an ornamental design for a stapler in accordance with my invention;

FIG. 2 is a right side elevational view thereof;

FIG. 3 is a top plan view thereof;

FIG. 4 is a bottom plan view thereof;

FIG. 5 is a front elevational view thereof; and,

FIG. 6 is a rear elevational view thereof. 

The ornamental design for a stapler, as shown and described. 